Ok, sorry about the double post here.
Neptune, let's get your configuration down first. Hope you've have your coffee, cause this might be a long post. If at any point you have questions, please ask them as you don't want to go buy the wrong stuff.
Yes you are correct. You're going to have 2 power supplies. I'll try to get some websites, and part numbers for you either later tonight, or tomorrow. I'll PM you with that info, and post this so anyone else reading can see this general info. Each power supply with be producing roughly 6.5 amps. I don't know how to put it nicely, but your calculations are not correct. Your power supply will provide 6.5 amps. You will spilt that up into 6 strings of LEDs, each string consisting of 5 LEDs if not for the driver. The drivers dictate exactly how much current will run through that string. So, for each string, 700mA will be flowing through that path, regardless of how many LEDs are on the string. 700mA times 6 strings is 4.2 amps. Theoretically you will only need your power supply to produce 4.2 amps. You will want the 6.5 amps just to have to some comfort room(details are more complicated than needed, maybe even run a fan. But you for sure don't want to add everything up and have your current draw equaling your max rating, as you don't want to run anything in this system at it's max rating. You do not add up currents when you are talking about a series. On the other hand, when you have 6 strings in parallel, that's when you add up the 700mA. We can talk about the different voltages when we design the drivers.
The driver will be another issue. You can use a bread board like I have been using for simple, prototyping a driver. If SCI and I can work on some things collectively, maybe we can produce a simple kit that could be put together without much worrying on your part. BUT, you'll have to wait for things to pan out there cause I myself aren't done with configurations and whatnot.
Some corrections to your last post. Having circuitry in parallel vs in series has no difference on the survivablility of the parts involved. It's a matter of circuit dynamics, and takes a lot of reading and/or a couple classes to get down. Part of my major required me to take Intro to Electrical Circuits at my school.
And lastly, I have yet to buy anything from the shack that is dirrectly related to my DIY build. Yes, I bought some parts from there to prototype some stuff, but in the end, nothing from the shack will be on my build other than a switch or two.
When are you planning on starting this build for your tank? I'll PM you with some links to the websites I've used.